Method of decorating silk fabrics



' Patented D0912;

UNITED STATESv fPa'ifaNr oer-res I mno'n or nlooaa'rmq em: rsmuos No Drawing.

This invention relates to'the art of decorating fabrics, and particularly silk fabrics. and it contemplates decorating a silk fabric (by. which I mean a fabric including silk, although it may i also include other fibers) by first printing thereon, in some selected design a resist and then subjecting the fabric to the action of an agent which .willsoactuponthesilkfibersastoeifectsucha structuralchangeinth's areasof the fabricuncoveredbythe-resistthatapronounceddecorative contrast'between such areas and those covered by the resist will result,

' I have found that if the fabric first, as by printing. having the resist deposited thereon in 1' some selected design. is treated with formic acid.

preferably concentrated; fora given time and then rid of the resist and the acid the result is that the threads of the areas unprotected by the. I

resist and hence attacked by the acid assume a morestraightened form'and more compact relation to each other than before the treatment, 02' than the threads in the resist-protected areas. the

straightened form being the result of shrinkage of the threads. affected, andwhen the resist is re- 95 moved this shrinkage become effective to crinkle the threads in the areas which were protected by the resist. In the preferred practice the gum is previously removed from the silk. as by boiling oi! the fabric before the treatment, though my invention does not exclude the treatment .ofgoods composed of or including silk yarns boiled of! before weaving; when the silk is treated in the raw itis found that the action of the formic acid thereon is retarded, evidently because of the presonce of the gum in the silk.' wherefore the acid has time not onlyto act unfavorably on the-fibers buttosoften the Further, in the effort to make practical use of this invention in the decorating of fine silk fab- 40 rics I have found that formic acid cannot be successfully used 'on a resist-protected fabric of which the resist substance is the ordinary printinggum,sincesuchresistsubstanceissoreadily soluble in acid that satisfactory results are im-' possible. the resist in places becoming wholly or partially removed by the acid and spoiling the intended design on the fabric because the .acid attains access to portions of the fabric assumed to be protected by the resist. Hence my invention to the formic acid. 7 y

In carrying out my invention I prefer to follow this procedure:

blllioati '1: April Serial No. 0

further contemplates that specific method which. involves. depositing the hereinafter specified resist on the fabric and then subiecting'the fabric is, in: 5.12.5 o1. s-se) If the silk yarns of the fabricvare not boiled off previous to weavingthe fabric itself is first boiled oil. then tentered. It is then resistprinted. using for the resist a composition consistingofagumfromtheacaciaclasa'asgum arabic, and an ordinary printing gum, .as shiras or corea, in the approximate proportions of 56 to V fl'heprintinggumisrequiredinorderto. aiford the compositionthe Mcity and other qualities which willadapt it to cling if to the printing rollers and not b'e disturbed bythe doctor blade of the printing e when the composition is made to. occupy the engraved areas of the printing roller: and the gum arabic or equivalent is present to give the composition the T0 desired resistance to solubility in the presence of the concentrated formic acid. a

The fabric is then run through a cold bath of concentrated formic acid so that no portion thereof remains in'the hath more than thirty seconds, approximately, it being found thatflan appreciably less period will not develop the full possible degree of decorative contrast desired and that appreciably greater period will allow'the acid to have some dissolving influence on the resist deposits, with the result that theintended design would be more or less disfigured. The fabric is then run through a cold-water wash. which nullifles the action of the acid on the silk and-in fact removes it and dissolves and so also 35 removes the resist both components of which are 7 of course solublein water: this bath may be still or quiescent so that the formic acid deposited therein may be recovered. Finally it is washed in a running-water bath. The formic acid bath will be improved in itsaction on the silk if to each liter thereof -1 to 50 cc. of concentrated sulphuric acid is added.

- It'will beunderstood that formic acid inconcentrated form (or low in water content) is used to reduce the tendency thereof to dissolve the gum of .the resist. a

One resultof my method is that when the fabric is following the treatment the color appears mo in two different shades, that where the resist was absent presenting a darker shade than thatwhere the resist was present.

Again, if after the formic acid treatment the fabric is weighted and then dyed, the darker areas will be-thow attacked by the formic acid (or not covered by the resist); this is evidently because the fornuc acid reduces the responsiveness of the iibers to weighting and sincesuch fibers are consequently deficiently. weighted they take up the no Havinz'thus fully described my invention what I claim is: i a

1.--The-method of decorating; a silk fabric which consists in depositing thcreon in a'seiectcd de-.-,

signapiasticreaistcomprisina aprintinggum anda gum from acacia arabica in substantially] the proportions .of one-third to two-thirds, respectively, then subjecting the fabric to a formic acid bath, and finally nullifyin: the action of the acidonthcsiikandremovinzthcresist."

2; The method of decorating a. 5m; ram-1c which consists in depositing thereon in a" selected design a plasticresist comprisinza printing sum and a sum from were. arabica in substantially the proportions of one-third to two-thirds. respectively. then subjecting the fabric to a concentrated formic acidbath so that each part of the fabric wiii'be so subjected for about thirty seconds, and iinaiiy nullifying the action of the acid on th silk' and removing the resist. 

